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                [Swerc2008]First Knight                </h1>
                <p>时间限制：1s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
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                                <h3>题目描述</h3><p><p><span style="font-size: medium"><img height="321" width="777" alt="" src="../file/3317_0.jpg" /></span></p>
<p></p>
<div class="O" v:shape="_x0000_s1026">
<div style="mso-line-spacing: '100 -48 0'; mso-margin-left-alt: 230; mso-text-indent-alt: 52; mso-char-wrap: 1; mso-kinsoku-overflow: 1"><span style="font-size: medium"><span style="left: -2.91%; color: #3891a7; font-family: &quot;Wingdings 2&quot;; position: absolute; top: 0.22em; mso-special-format: bullet; mso-color-index: 4"></span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">一个</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN"><i>m</i></span><span lang="EN-US" style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">&times;</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN"><i>n</i></span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">的棋盘，左上至右下编号为</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">(1, 1)</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">至</span><span style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial"> </span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">(</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN"><i>m</i></span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">, </span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN"><i>n</i></span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">)</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">，并给定每个格子到周围四个格子的概</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">率　　。 </span></span></div>
<div style="mso-line-spacing: '100 -48 0'; mso-margin-left-alt: 230; mso-text-indent-alt: 52; mso-char-wrap: 1; mso-kinsoku-overflow: 1"><span style="font-size: medium"><span style="left: -2.82%; color: #3891a7; font-family: &quot;Wingdings 2&quot;; position: absolute; top: 0.22em; mso-special-format: bullet; mso-color-index: 4"></span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">一个骑士从</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">(1, 1)</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">开始，按照给定概率走，问到</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">达</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">(</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN"><i>m</i></span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">, </span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN"><i>n</i></span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">)</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">的期望步数。 </span></span></div>
<div style="mso-line-spacing: '100 -48 0'; mso-margin-left-alt: 230; mso-text-indent-alt: 52; mso-char-wrap: 1; mso-kinsoku-overflow: 1"><span style="font-size: medium"><span style="left: -2.8%; color: #3891a7; font-family: &quot;Wingdings 2&quot;; position: absolute; top: 0.22em; mso-special-format: bullet; mso-color-index: 4"></span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">题目保证从任一格开始到</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">(m, n)</span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">的概率均为</span><span lang="EN-US" style="mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial; mso-fareast-language: ZH-CN">1 </span><span style="font-family: 宋体; mso-fareast-font-family: 宋体; mso-hansi-font-family: Arial">。</span></span></div>
</div></p><hr/><h3>输入格式</h3><p><p><img height="456" width="781" alt="" src="../file/3317_0.jpg" /></p></p><hr/><h3>输出格式</h3><p><p><img height="78" alt="" width="779" src="../file/3317_0.jpg" /></p></p><hr/><h3>样例输入</h3><pre>2 2
0.01 0.50
0.00 0.00
0.99 0.00
0.50 0.00
0.00 0.00
0.50 0.00
0.00 0.50
0.00 0.00
1 5
0.0 0.0 0.0 0.0 0.0
1.0 0.1 0.7 0.5 0.0
0.0 0.0 0.0 0.0 0.0
0.0 0.9 0.3 0.5 0.0
3 3
0.000001 0.0 1.0
0.0 1.0 1.0
0.0 0.0 0.0
0.999999 1.0 0.0
1.0 0.0 0.0
0.000001 0.000001 0.0
0.0 0.0 0.0
0.0 0.0 0.0
0.999999 0.0 0.0
0.0 0.0 0.0
0.0 0.0 0.0
0.0 0.999999 0.0
0 0

</pre><hr/><h3>样例输出</h3><pre>4.0
41.142857142857146
7.999994000002</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>WCMG提供SPJ</p>
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